Problem: Khan.scratchpad.disable(); Kevin sells magazine subscriptions and earns $$2$ for every new subscriber he signs up. Kevin also earns a $$39$ weekly bonus regardless of how many magazine subscriptions he sells. If Kevin wants to earn at least $$40$ this week, what is the minimum number of subscriptions he needs to sell?
Answer: To solve this, let's set up an expression to show how much money Kevin will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Kevin wants to make at least $$40$ this week, we can turn this into an inequality. Amount earned this week $\geq $40$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $40$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $2 + $39 \geq $40$ $ x \cdot $2 \geq $40 - $39 $ $ x \cdot $2 \geq $1 $ $x \geq \dfrac{1}{2} \approx 0.50$ Since Kevin cannot sell parts of subscriptions, we round $0.50$ up to $1$ Kevin must sell at least 1 subscriptions this week.